Wiper Motor

Most cars use one motor with a linkage; some use two motors. A park switch stops the wipers in the rest position. Rear wipers have their own motor. Wiper blades should be replaced when they streak or chatter; worn blades also make the motor work harder on a dry or icy screen.

An electric motor with a worm gear turns a crank that moves the wiper arms back and forth.

Wipers that stop in the wrong place or run slowly can mean a worn motor or linkage. Lifting frozen wipers before switching on protects the motor.